How should two short-term tests be placed when deployed as duplicates?

When deploying two short-term radon tests as duplicates, they should be placed at the same time and location, ideally 4-8 inches apart. This method ensures that both tests are exposed to the same environmental conditions and air quality, which allows for a more accurate comparison of the radon levels they measure. By placing them close together, any variations in readings are more likely due to random fluctuations rather than differences in environmental factors or placement, thus improving the reliability of the results.

Testing simultaneously at the same site also eliminates potential issues related to temporal variations in radon levels that might affect readings if the tests were conducted at different times. The recommendation to position them 4-8 inches apart specifically helps avoid interference in measurements that could occur if they were placed too close together. This approach gives a clearer assessment of the radon concentration, which can be vital for determining necessary mitigation actions.